1. Field of the Invention
The present invention relates to a stapler and a component of the stapler, and more particularly to a stapler and a multi-inclined anvil structure thereof.
2. Description of Related Art
A conventional stapler has an anvil. The anvil is applied for clinching two legs of a staple, such that sheets of paper can be stapled and assembled, and the clinched staple can be kept from piercing through sheets of paper or injuring a user.
With reference to FIGS. 8 to 9B, a conventional anvil of a stapler comprises an anvil body 50. A top of the anvil body 50 is recessed and has two inclined portions 51, a planar portion 52 and two bending portions 53. The recessed top of the anvil body 50 has a uniform width. A depth B of the top of the anvil body 50 is 0.8 millimeters. The inclined portions 51 are respectively formed on a front side and a rear side of the top of the anvil body 50, and are formed opposite to each other. The front side of the anvil body 50 is distal from a pivot position of the stapler, and the rear side of the anvil body 50 faces to the pivot position of the stapler. The planar portion 52 is formed on a bottom surface of the recessed top of the anvil body 50. The planar portion 52 is planar relative to the top of the anvil body 50. The bending portions 53 are respectively connected with two ends of the planar portion 52, and the bending portions 53 are curved. When the stapler is stapling, an arm of the stapler is pressed downward, two legs of the staple are respectively bent by the two bending portions 53, and the legs of the staple extend and are flattened along the planar portion 52.
However, the width of the recessed top of the conventional anvil body 50 is uniform from a front side to a rear side of the anvil body 50, and the planar portion 52 is horizontal relative to the top of the anvil body 50. Therefore, during stapling, the legs of the staple piercing through the sheets of paper are not positioned easily, and a stapling quality is relatively unstable. When the stapler is applied to staple a few sheets of paper, such as two sheets, a sliding phenomenon occurs at the legs of the staple easily. When the stapler is applied to staple many sheets of paper, such as more than twenty sheets, a piercing width between the legs of the staple piercing through the paper becomes narrowed, such that the legs of the staple cannot be clinched well easily. The legs of the staple that are not clinched well will injure a user easily.
To resolve the aforementioned problems, with reference to FIG. 6C of TW patent No. I409146, an anvil body having an inclined bottom surface is disclosed. A front side of the inclined bottom surface of the anvil body is higher than a rear side of the inclined bottom surface of the anvil body. When the stapler is stapling, although the legs of the staple can be kept from sliding toward the front side, the piercing width between the legs of the staple piercing through the sheets of paper still becomes narrowed when stapling many sheets of paper, such that the legs of the staple are not clinched well and flattened easily.
Further with reference to TW patent No. I409146, the anvil body has a horizontal bottom surface and an inclined bottom surface. The horizontal bottom is located at a rear side of the inclined bottom surface, and the inclined bottom surface of the anvil body is formed as a structure that has a high front and a low rear. When the stapler is stapling a few sheets of paper, a piercing working plane of the staple is the horizontal bottom surface, and a piercing direction of the staple is perpendicular to the horizontal bottom surface. When the stapler is stapling many sheets of paper, the legs of the staple approach toward the inclined bottom surface. However, the bottom of the anvil body needs to form the horizontal bottom surface and the inclined bottom surface. As a result, during stapling, the legs of the staple are relatively harder to be positioned. Furthermore, the bottom of the anvil body has a relatively larger size along an extension direction between the front side and the rear side of the anvil body, such that during stapling, the legs of the staple may be askew relative to the anvil body, and a manufacturing cost of the anvil body with the anvil structure is increased.